Question

Give an example of a chemical reaction for each of the following situation: (a) A change in colour is observed. (b) A gas is evolved.​

Answer 1

Chemical reaction between copper sulphate solution and iron metal. In this reaction, blue colour of copper sulphate solution changes to light green colour due to the formation of iron sulphate.

Copper sulphate + Iron

⟶

Iron sulphate + Copper

(blue) (grey) (light green) (brown)

b) When baking soda and vinegar are mixed together then a chemical change takes place and bubbles of carbon dioxide gas are formed along with some other substances.

Baking soda + vinegar

⟶

sodium acetate + carbon dioxide + water